A few words of thanks would be greatly appreciated.

Optimize Firefox (completely)

Mozilla Firefox can be configured to give its best performance by disabling anti-phishing protection. In a few simple steps, it is possible to disable the security features on Firefox in order to optimize the browser. Although, it is not advisable to surf the internet without security features, including anti-phishing protection, enabled, it helps to speed up the browser considerably. Alternative software can be installed that provides protection from malware and spyware without reducing the performance of the web browser. It is now easy to optimize Firefox for best performance and one can use the web without compromising security at any level.

To optimize and improve the Firefox browsing speed, start by following this article.
In addition, the tips below may allow you to improve performance further.

WARNING: The following trick disables certain security features, so you use it at your own risk.
  • Advanced users should be able to apply this trick without problem
  • Novice users should install additional WOT to protect them from malicious sites
  • In all cases, make you sure have up-to-date antivirus software


Firefox's anti-phishing system is designed to protect you from certain malicious sites. The list of sites to avoid is provided by Google and stored in the urlclassifier3.sqlite file in your Firefox profile.

This file is about 30MB and Firefox constantly consults it to check all the addresses you visit. This has a significant impact on performance. You can disable this system to improve performance.

Getting started

  • Launch Firefox
  • In the address bar, type about:config
  • Confirm if needed
  • In the filter, type safe
  • In the Settings list, double-click on the following parameters and set them to false:
    • browser.safebrowsing.enabled
    • browser.safebrowsing.malware.enabled
  • Close Firefox and wait several seconds
  • In your Firefox profile, delete the file urlclassifier3.sqlite
    • This poses no long-term risk - Firefox can recreate it if required
  • Restart Firefox
  • You should see an improvement


Reactivating the anti-phishing system in Firefox is very simple:
  • Follow the above procedure to set the two parameters back to true.

Urlclassifier3.sqlite: The file will automatically be recreated by Firefox.

Additional notes

  • Anti-phishing systems play an important role in protecting your computer and information
  • WOT offers better protection than the anti-phishing in Firefox and does not slow the loading of pages
  • You can learn more about WOT on Kioskea
  • Thanks to sebsauvage for this tip

A few words of thanks would be greatly appreciated.

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